This project, entitled "Missense Suppression and Mutationally Altered tRNAs", proposes the use of missense suppression as a means of obtaining tRNAs with mutationally altered functions and interactions. It aims at the preliminary characterization of the altered tRNAs by column chromatography, determination of changes in nucleotide sequence, and correlation of altered sequence with altered functions and other changes in tRNA structure and interactions. The results of these studies are necessary to form the basis for the possibility of "tRNA therapy", whereby specifically altered suppressor tRNA molecules may be employed to phenotypically correct defects in human cells subject to premature aging or neoplastic disease.